// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_DELEGATE_H_
#define UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_DELEGATE_H_

#include "ui/views/views_export.h"

namespace gfx {
class Canvas;
class Insets;
class Path;
class Point;
class Size;
}

namespace ui {
class Accelerator;
class KeyEvent;
class MouseEvent;
class TouchEvent;
}

namespace views {

class InputMethod;

// Implemented by the object that uses the HWNDMessageHandler to handle
// notifications from the underlying HWND and service requests for data.
class VIEWS_EXPORT HWNDMessageHandlerDelegate {
public:
    virtual bool IsWidgetWindow() const = 0;

    // TODO(beng): resolve this more satisfactorily vis-a-vis ShouldUseNativeFrame
    //             to avoid confusion.
    virtual bool IsUsingCustomFrame() const = 0;

    virtual void SchedulePaint() = 0;
    virtual void EnableInactiveRendering() = 0;
    virtual bool IsInactiveRenderingDisabled() = 0;

    virtual bool CanResize() const = 0;
    virtual bool CanMaximize() const = 0;
    virtual bool CanMinimize() const = 0;
    virtual bool CanActivate() const = 0;

    // Returns true if the delegate wants mouse events when inactive and the
    // window is clicked and should not become activated. A return value of false
    // indicates the mouse events will be dropped.
    virtual bool WantsMouseEventsWhenInactive() const = 0;

    virtual bool WidgetSizeIsClientSize() const = 0;

    // Returns true if the delegate represents a modal window.
    virtual bool IsModal() const = 0;

    // Returns the show state that should be used for the application's first
    // window.
    virtual int GetInitialShowState() const = 0;

    virtual bool WillProcessWorkAreaChange() const = 0;

    virtual int GetNonClientComponent(const gfx::Point& point) const = 0;
    virtual void GetWindowMask(const gfx::Size& size, gfx::Path* mask) = 0;

    // Returns true if the delegate modifies |insets| to define a custom client
    // area for the window, false if the default client area should be used. If
    // false is returned, |insets| is not modified.
    virtual bool GetClientAreaInsets(gfx::Insets* insets) const = 0;

    // Returns the minimum and maximum size the window can be resized to by the
    // user.
    virtual void GetMinMaxSize(gfx::Size* min_size,
        gfx::Size* max_size) const = 0;

    // Returns the current size of the RootView.
    virtual gfx::Size GetRootViewSize() const = 0;

    virtual void ResetWindowControls() = 0;

    virtual gfx::NativeViewAccessible GetNativeViewAccessible() = 0;

    // Returns true if the window should handle standard system commands, such as
    // close, minimize, maximize.
    // TODO(benwells): Remove this once bubbles don't have two widgets
    // implementing them on non-aura windows. http://crbug.com/189112.
    virtual bool ShouldHandleSystemCommands() const = 0;

    // TODO(beng): Investigate migrating these methods to On* prefixes once
    // HWNDMessageHandler is the WindowImpl.

    // Called when another app was activated.
    virtual void HandleAppDeactivated() = 0;

    // Called when the window was activated or deactivated. |active| reflects the
    // new state.
    virtual void HandleActivationChanged(bool active) = 0;

    // Called when a well known "app command" from the system was performed.
    // Returns true if the command was handled.
    virtual bool HandleAppCommand(short command) = 0;

    // Called from WM_CANCELMODE.
    virtual void HandleCancelMode() = 0;

    // Called when the window has lost mouse capture.
    virtual void HandleCaptureLost() = 0;

    // Called when the user tried to close the window.
    virtual void HandleClose() = 0;

    // Called when a command defined by the application was performed. Returns
    // true if the command was handled.
    virtual bool HandleCommand(int command) = 0;

    // Called when an accelerator is invoked.
    virtual void HandleAccelerator(const ui::Accelerator& accelerator) = 0;

    // Called when the HWND is created.
    virtual void HandleCreate() = 0;

    // Called when the HWND is being destroyed, before any child HWNDs are
    // destroyed.
    virtual void HandleDestroying() = 0;

    // Called after the HWND is destroyed, after all child HWNDs have been
    // destroyed.
    virtual void HandleDestroyed() = 0;

    // Called when the HWND is to be focused for the first time. This is called
    // when the window is shown for the first time. Returns true if the delegate
    // set focus and no default processing should be done by the message handler.
    virtual bool HandleInitialFocus(ui::WindowShowState show_state) = 0;

    // Called when display settings are adjusted on the system.
    virtual void HandleDisplayChange() = 0;

    // Called when the user begins or ends a size/move operation using the window
    // manager.
    virtual void HandleBeginWMSizeMove() = 0;
    virtual void HandleEndWMSizeMove() = 0;

    // Called when the window's position changed.
    virtual void HandleMove() = 0;

    // Called when the system's work area has changed.
    virtual void HandleWorkAreaChanged() = 0;

    // Called when the window's visibility is changing. |visible| holds the new
    // state.
    virtual void HandleVisibilityChanging(bool visible) = 0;

    // Called when the window's visibility changed. |visible| holds the new state.
    virtual void HandleVisibilityChanged(bool visible) = 0;

    // Called when the window's client size changed. |new_size| holds the new
    // size.
    virtual void HandleClientSizeChanged(const gfx::Size& new_size) = 0;

    // Called when the window's frame has changed.
    virtual void HandleFrameChanged() = 0;

    // Called when focus shifted to this HWND from |last_focused_window|.
    virtual void HandleNativeFocus(HWND last_focused_window) = 0;

    // Called when focus shifted from the HWND to a different window.
    virtual void HandleNativeBlur(HWND focused_window) = 0;

    // Called when a mouse event is received. Returns true if the event was
    // handled by the delegate.
    virtual bool HandleMouseEvent(const ui::MouseEvent& event) = 0;

    // Called when an untranslated key event is received (i.e. pre-IME
    // translation).
    virtual void HandleKeyEvent(ui::KeyEvent* event) = 0;

    // Called when a touch event is received.
    virtual void HandleTouchEvent(const ui::TouchEvent& event) = 0;

    // Called when an IME message needs to be processed by the delegate. Returns
    // true if the event was handled and no default processing should be
    // performed.
    virtual bool HandleIMEMessage(UINT message,
        WPARAM w_param,
        LPARAM l_param,
        LRESULT* result)
        = 0;

    // Called when the system input language changes.
    virtual void HandleInputLanguageChange(DWORD character_set,
        HKL input_language_id)
        = 0;

    // Called to compel the delegate to paint |invalid_rect| accelerated.
    virtual void HandlePaintAccelerated(const gfx::Rect& invalid_rect) = 0;

    // Called to forward a WM_NOTIFY message to the tooltip manager.
    virtual bool HandleTooltipNotify(int w_param,
        NMHDR* l_param,
        LRESULT* l_result)
        = 0;

    // Invoked on entering/exiting a menu loop.
    virtual void HandleMenuLoop(bool in_menu_loop) = 0;

    // Catch-all message handling and filtering. Called before
    // HWNDMessageHandler's built-in handling, which may pre-empt some
    // expectations in Views/Aura if messages are consumed. Returns true if the
    // message was consumed by the delegate and should not be processed further
    // by the HWNDMessageHandler. In this case, |result| is returned. |result| is
    // not modified otherwise.
    virtual bool PreHandleMSG(UINT message,
        WPARAM w_param,
        LPARAM l_param,
        LRESULT* result)
        = 0;

    // Like PreHandleMSG, but called after HWNDMessageHandler's built-in handling
    // has run and after DefWindowProc.
    virtual void PostHandleMSG(UINT message,
        WPARAM w_param,
        LPARAM l_param)
        = 0;

    // Called when a scroll event is received. Returns true if the event was
    // handled by the delegate.
    virtual bool HandleScrollEvent(const ui::ScrollEvent& event) = 0;

    // Called when the window size is about to change.
    virtual void HandleWindowSizeChanging() = 0;

    // Called when the window size has finished changing.
    virtual void HandleWindowSizeChanged() = 0;

protected:
    virtual ~HWNDMessageHandlerDelegate() { }
};

} // namespace views

#endif // UI_VIEWS_WIN_HWND_MESSAGE_HANDLER_DELEGATE_H_
